The invention is related to the field of data storage, and in particular, to a tape cartridge library for managing, storing, and providing a plurality of tape cartridges for access to at least one tape drive.
A popular device for handling large amounts of information in a data processing system is an automated tape cartridge library. Tape cartridge libraries store and manage multiple tape cartridges containing magnetic tape media on which data is stored. Tape cartridge libraries typically include a plurality of fixed tape cartridge storage locations, at least one read/write tape drive, and a tape cartridge retrieval/transport mechanism, known in the art as a xe2x80x9ccartridge picker.xe2x80x9d
Unfortunately, tape cartridge libraries suffer from numerous drawbacks. One major drawback in tape libraries is their overall size, primarily due to the necessity of storing and managing the large number of tape cartridges. In tape libraries, the tape cartridge storage locations are arranged in predetermined arrays of uniquely identified cells with each cell containing a single tape cartridge. In some cases, the array of cells is configured in a bookshelf arrangement. This type of arrangement, however, requires the use of a multi-axis cartridge picker that translates along an x, y, and/or z axis to exchange the individual tape cartridges with a tape drive(s).
In other cases, such as disclosed in U.S. Pat. No. 5,847,897, the array of cells is vertically oriented in a carousel style cartridge magazine that rotates about a central axis to position tape cartridges for selection by a stationary cartridge picker. Unfortunately, the vertical orientation of the tape cartridges in the magazine, while necessary to the operation of the carousel, and use of a stationary cartridge picker, significantly adds to the overall height and size of the library. Additionally, the vertical orientation of the tape cartridges requires that the tape drive(s) also be vertically oriented to permit the picker to pass a tape cartridge from the magazine to the drive without a complicated re-orientation of the cartridge that would result in the need for additional space within the library.
The cartridge picker is another factor contributing to the size of tape library systems. Cartridge pickers automatically exchange the individual tape cartridges between their storage locations and the tape drive. Different types of pickers accommodate various tape cartridge arrangements in different tape cartridge libraries. One example of a tape cartridge picker utilizes a rotatable robotic arm with an optical sensor for selecting and retrieving the correct tape cartridge and transporting the tape cartridge to a tape drive. Another example of a tape cartridge picker utilizes a linear robotic mechanism that moves along an X-Y translation or about a pivot in a rotary motion to select, retrieve, and transport tape cartridges to a tape drive. Unfortunately, tape cartridge pickers are complex mechanisms that require a significant amount of space to maneuver and translate among the multitude of storage locations to retrieve and deliver tape cartridges to tape drives.
The present invention solves the problems outlined above and advances the art by providing a tape cartridge library system, termed xe2x80x9cautoloader/library systemxe2x80x9d herein. The present autoloader/library system includes at least one read/write tape drive, a tape cartridge picker, a single tape cartridge interface, and a pair of tape cartridge transport magazines within a compact and volumetrically efficient form factor that fits into a conventional library rack mount cabinet. The autoloader/library system is a complete tape cartridge library that stores, manages, and automatically exchanges a plurality of tape cartridges between the tape drive, the single cartridge interface, and the tape cartridge transport magazines. In one example of the present invention the autoloader/library system is configured to store and manage sixteen tape cartridges in a form factor measuring less than three and one half inches high, less than twenty eight inches deep, and less than eighteen inches wide.
The autoloader/library system can function as a traditional tape cartridge library where the plurality of tape cartridges stored in the magazine(s) are managed by the autoloader/library system, or the autoloader/library system can function to present a plurality of scratch (blank) tapes to the tape drive(s) for the writing of data thereon. In this latter application, the magazine functions to queue a plurality of scratch tapes for the tape drive(s) so that data can be written on each of the scratch tapes without the necessity of an operator having to manually load scratch tapes into the tape drive(s).
The autoloader/library system is architected such that the components are substantially coplanar. In one example of the present invention, a pair of tape cartridge transport magazines is utilized to receive and store a plurality of individual tape cartridges in a horizontal relationship. The magazines transport the individual tape cartridges in a vertical closed loop within the magazines so that individual tape cartridges can be positioned for selection by the cartridge picker. Advantageously, the cartridge picker does not translate in three dimensions as in prior art tape cartridge library systems, but instead simply rotates within a stationary picker base to position for the exchange of tape cartridges with the tape drive, the tape cartridge transport magazines, and a single tape cartridge interface. The single tape cartridge interface is configured to exchange tape cartridges between the autoloader/library system and an operator.
The autoloader/library system is also configured to mechanically and electrically interconnect with other substantially identical autoloader/library systems by stacking multiple autoloader/library systems to provide expandability and scalability as a matter of design choice. Once stacked, the multiple autoloader/library systems could each include their own tape cartridge transport magazines, tape drive, and cartridge picker or could share elements such as the single tape cartridge interface, tape cartridge transport magazines, tape drives and cartridge pickers. In addition, stacked autoloader/library systems may also share tape cartridges to provide efficient load balancing and operation.
A first advantage of the present autoloader/library system is the use of the transport mechanisms in the tape cartridge transport magazines to position tape cartridges for selection by the cartridge picker. This significantly limits the amount of the travel and space required to operate the cartridge picker. The cartridge picker simply rotates between the tape cartridge transport magazines, the tape drive, and the single cartridge interface to provide a fast efficient exchange of tape cartridges. A second advantage of the present autoloader/library system is the horizontal orientation of the cartridges in the magazines that permit coplanar components in the autoloader/library system to facilitate the compact form factor. A third advantage of the present autoloader/library system is the independent operation of the magazines, cartridge picker, tape drive, and single cartridge interface. During operation, the magazine(s) can inventory or queue cartridges for retrieval by the picker while the picker shuttles tape cartridges between various locations in the autoloader/library system and the tape drive(s) read and write data to a tape cartridge. A fourth advantage of the present tape cartridge transport magazine is that the tape cartridge transport magazines are interchangeable so that any one of the magazines will interface with any one of multiple magazine ports. A fifth advantage of the present autoloader/library system is the expandability and scalability provided by stacking multiple autoloader/library systems to expand capacity.